A wireless sensor network consists of sensor nodes with low cost and low energy consumption and can complete information perception, simple data processing, short-distance communication and other functions. The wireless sensor network is always a research hotspot due to the enormous application potential in aspects of battlefield surveillance, environment monitoring, industrial automation, agricultural production, etc. However, the sensor nodes are generally powered by a battery which is difficult to replace once deployed, causing a limitation to the life of the wireless sensor network. With respect to the problem of prolonging the life of the network, a double-layer wireless sensor network structure is proposed in the prior art. A small quantity of relay nodes with adequate energy and large communication radius are deployed in the double-layer structure network, and act as cluster heads. 1-hop neighbor sensor nodes send collected data to the relay nodes, and the relay nodes collect the data collected by the 1-hop neighbor sensor nodes and forward the data to convergent nodes. In the double-layer structure wireless sensor network, the sensor nodes can forward the collected information in an energy saving mode. Apparently, the relay nodes are of great importance in the double-layer structure wireless sensor network. However, the relay nodes have high cost. How to reduce the deployment cost of the relay nodes (reduce the number of the relay nodes) on the premise of ensuring network coverage and connectivity becomes a current research hotspot.
The existing deployment method with respect to the relay nodes comprises two phases: a geometric unit circle coverage phase and a network connectivity construction phase, wherein a geometric unit circle coverage algorithm mainly comprises a division-motion based manner, a grid based manner and a set coverage based manner. The algorithm complexity of the division-motion based manner has an exponential growth trend along with a division-motion factor; and for the algorithms of the grid based manner and the set coverage based manner, a final result is that more relay nodes are deployed. In general, the current geometric unit circle coverage algorithm has higher calculation complexity and higher deployment cost.
Although the design process of the wireless sensor network is limited by a cost factor, the network robustness remains a crucial problem in the design of the wireless sensor network. Therefore, a conventional method is to adopt the strategy of implementing 2-coverage on the sensor nodes, i.e., each sensor node is covered by at least two relay nodes. Traditionally, 2-coverage is designed on the basis of 1-coverage. For the sensor nodes covered by less than two relay nodes, only a 1-coverage algorithm is used for re-implementing simple coverage.